1. Field of the Invention
The invention relates to a sliding element, in particular a piston ring, a method for manufacturing a sliding element, a sliding system and a coating for a sliding element.
Sliding elements, such as eg piston rings, comprise running faces with which they are in sliding contact with a partner in the tribosystem. Hereby, it is essential for the required service life to be achieved including under the sometimes extreme requirements. In the case of piston rings this relates to, for example, the increasingly high cylinder pressures, direct injection, exhaust gas recirculation and other features of modern engines which increasingly stress the piston rings. This is compounded by new types of cylinder materials and the objective of minimising oil consumption.
2. Prior Art
To achieve the service life, sliding elements of this kind comprise anti-wear layers. These can be applied by thermal spray methods, galvanic methods, by nitriding or the methods of thin-layer technology.
DE 198 25 860 A1 describes a piston ring with a coating of a diamond-like carbon on its running face. This layer forms a permanently effective wear layer.
U.S. Pat. Nos. 6,279,913 B1 and 6,325,385 B1 describe piston rings which comprise a DLC (diamond-like carbon) layer, wherein there can be a nitrided layer between this layer and the piston ring material.
US 2005/0100701 A1 relates to a piston ring with a hard carbon layer in which the hydrogen content varies over the thickness.